JP2007199128A - Zoom lens barrel unit, imaging device, camera, personal digital assistant, and portable telephone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve small size, lightweight, reduction in the number in components, shortness of an assembling time, and reduction or the like of accumulated errors of the components while achieving variable power and focal point matching adjustment by one drive motor. <P>SOLUTION: Two-group moving frames 20 for holding a second lens group and three-group moving frames 30 for holding a third lend group are shared and screwed with helicoid screws of the inside of a main lens barrel, and rotational force of one drive motor 70 is transmitted to a rotational drive ring 50. The three-group moving frames 30 are rotated with two guide shafts 51 embedded in the rotational drive ring 50. In a prescribed angle range, the two-group moving frames 20 are continuously variably powered by straightly advancing and moving while integrally rotating the three-group moving frames 30 in one direction. Thereafter, engagement of the three-group moving frames 30 to the two-group moving frames 20 is temporarily released, and focal point matching adjustment is performed by rotationally straightly advancing and moving only the three-group moving frames 30 in a reverse direction of the above while holding a static state by the two-group moving frames 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel structure that can be mounted on a portable information terminal device such as a thin digital camera equipped with an image sensor or a mobile phone, and in particular, a focal length can be freely selected and set by zooming. Further, the present invention relates to a zoom lens barrel unit, an imaging device, a camera, a portable information terminal device, and a mobile phone that can be further adjusted in focus (focusing).

The recent trend toward commercialization of portable information terminal devices such as digital cameras and mobile phones has become more and more highly functional, but with regard to the appearance thickness, the tendency to be thinner and smaller is remarkable.
In particular, with regard to digital camera imaging optical systems, zoom magnification tends to increase, and along with this, the number of lenses in the optical system increases, and the drive mechanism of the zoom lens barrel becomes more complicated and more accurate. It is in. As a result, a high degree of dimensional accuracy is required for each component, and a high degree of accuracy is required for drive control.
In mobile phones as well, there is an increasing demand for mounting a zoom lens function as a photographing lens system as the functionality increases.
However, in spite of the demand for thinner and lighter weight, the lens configuration and zoom lens barrel drive mechanism are complicated, so the entire zoom lens barrel unit is enlarged and only stored. The current situation is that there is limited space.

Recently, a so-called digital zoom system has been proposed as a solution to compensate for these shortcomings as much as possible, by processing an image of a digital signal obtained by single lens photography to give an impression that the angle of view changes.
As is well known, according to this method, it is possible to obtain a feeling of zooming effect. However, if the magnification is increased more than necessary, there is a disadvantage that the image quality is deteriorated.
As a means for eliminating or complementing these drawbacks as much as possible, image processing is performed by combining a zoom lens barrel mechanism having an optical system capable of selectively setting two focal lengths (wide angle, telephoto) and the digital zoom method. Therefore, a method for minimizing image degradation and obtaining a continuous zooming effect has been proposed. However, in the above-described method, a space for arranging a plurality of actuators for switching to two focal lengths (wide angle, telephoto) and actuators for adjusting the focal point is necessary, and the entire unit is enlarged. There was a point.

Still another method is introduced in Patent Document 1 and Patent Document 2.
The photographic optical lens configuration includes a first lens group having a negative focal length from the subject side, a second lens group having a positive focal length, and a third lens group having a negative focal length, and the first lens. The lens group is fixed, and the second lens group and the third lens group move on the optical axis in a straight line according to the rotation of the cylindrical cam device, so that zooming and focusing adjustment are possible.
At the time of zooming, the second lens group and the third lens group move straight in the optical axis direction according to the rotation of the cam device while maintaining a predetermined air interval on the cylindrical cam.
During focus adjustment, the second lens group is disposed on a flat surface that does not move in the front-rear direction even when the cylindrical cam device rotates. On the other hand, the third lens group moves linearly in the optical axis direction while sliding on the tapered surface as the cylindrical cam device rotates, so that the air gap between the second lens group and the third lens group is increased. Change. As a result, focus adjustment can be adjusted.
At this time, when the air space between the second lens group and the third lens group is narrowed, that is, the third lens group moves from the imaging surface side to the subject side direction, the subject distance is changed from the closest side to the infinite side, On the other hand, when the air gap between the second lens group and the third lens group is increased, that is, when the object lens moves straight from the object side to the imaging surface side, the object distance moves from the infinite side to the close side.

Certainly, according to the above method, zooming and focusing adjustment can be performed with only one actuator. However, since there is a limit to the amount of movement of the second lens group and the third lens group in the optical axis direction, it is difficult to arrange a large number of flat cam portions necessary for focus matching adjustment. For these reasons, even if it is desired to select step zoom with a multifocal length, there is a difficulty that only about three points of wide angle, intermediate and telephoto can be set and selected.
Apart from this, a zoom lens mirror of the second group method (first lens group, second lens group) is also adopted in Patent Document 3, Patent Document 4, and Patent Document 5, and is a generally well-known method. There is a tube. An outer barrel, an inner barrel, a two-group moving frame, a rectilinear key, a fixed frame, and the like, and an outer barrel that is screwed with a helicoid screw formed in the fixed frame are provided by a motor disposed outside. It moves straight forward by power.
In addition, the inner lens barrel that houses the first lens group, the inner lens barrel that houses the shutter unit, and the helicoid screw and screw disposed inside the outer lens barrel are screwed into the inner helicoid screw of the outer lens barrel. At the same time, a second group moving frame that slides on a cam groove provided on the inner helicoid screw of the outer barrel and mounts the second lens group is predetermined for the first lens group and the second lens group. It moves straight on the optical axis while keeping the air gap. The amount of movement of the first lens group at this time is structured to move back and forth by the sum of the lead amounts of the respective helicoid screws formed around the outer lens barrel and the inner lens barrel.

Further, the second lens group is configured to move back and forth based on the sum of the displacement amount of the cam attached to the inner wall of the outer barrel and the helicoid lead amount of the outer barrel. As a result, in order to accurately manage the air spacing, back focus, etc. of the first lens group and the second lens group, components such as cam grooves and cam follower pins are suppressed at the same time as the occurrence of cumulative errors in each helicoid component is suppressed. It is required to strictly control the accuracy.
In addition, in focus adjustment, in addition to the drive motor for zooming, it is necessary to move further straight with another actuator, as well as a flexible wiring that sends a drive signal and current. .
As a result, a large amount of space is required for the arrangement of the parts and the like, and at the same time, the structure becomes more and more complicated, which not only increases the overall structural dimensions but also increases the unit price of the parts. There is a problem that assembly time longer than expected is required.

  When the zoom lens barrel structure as described above is adopted as a driving mechanism for a photographing lens system in a mobile phone or the like, as a result of a complex barrel configuration, there has been no problem in a camera compatible with a silver salt film. Accumulated errors such as eccentricity error and inclination error become a more serious problem than expected, and it can be imagined that it is difficult to ensure the machining and assembly accuracy of cam grooves and the like.

JP 2005-77713 A JP 2005-77714 A Utility model registration No. 2535052 JP-A-5-297259 JP-A-8-313784

As described above, when the prior art method is adopted, a lens barrel having a multilayer structure is used as a driving unit of the optical lens system, and thus a driving mechanism having a complicated configuration is required to obtain a zooming function and a focus matching adjustment function. In addition to this, there is a problem that the outer diameter is enlarged, and an actuator for zooming and focusing adjustment is required independently.
In order to solve such problems, the present invention simplifies the drive mechanism with a single-layer structure barrel instead of a conventional multilayer structure, and a drive mechanism for a single drive motor. The goal is to achieve both continuous zooming and focus adjustment functions at the same time. In addition, the movement change during driving of the lens system is uniformly and smoothly managed, the drive structure is simplified, the accuracy is facilitated, and the small size, light weight and thinning can be achieved. It has other purposes.

In order to achieve the above object, a zoom lens barrel unit according to the first aspect of the present invention includes at least a first lens group having a negative focal length, a second lens group having a positive focal length, and a negative focal length. In the optical system in which the first lens group is fixed and the second lens group and the third lens group rotate and move in the optical axis direction,
A second group moving frame that holds the second lens group and has an outer helicoid screw formed in the periphery;
A third group moving frame that holds the third lens group and has an outer helicoid screw formed in the periphery;
A main barrel having an inner helicoid screw formed on the inner wall so that the second group moving frame and the third group moving frame can be rotated and moved in a straight line while being screwed together;
A rotation drive ring in which either one of the second group moving frame or the third group moving frame is rotated and linearly moved, and a guide shaft is implanted and fixed in parallel with the optical axis;
A single drive motor that rotationally drives the rotary drive ring;
When the air gap distance between the second lens group and the third lens group is expanded to a predetermined interval in accordance with the zooming operation by the rotation in one direction of the rotary drive ring in conjunction with the drive motor, The drive motor is rotated in the opposite direction to adjust the focus matching by moving the air gap between the second lens group and the third lens group in the reduction direction.
When the air gap between the second lens group and the third lens group is reduced to a predetermined interval in accordance with a zooming operation by rotation in the other direction of the rotary drive ring in conjunction with the one drive motor. The drive motor is rotated in a direction opposite to the above, and the air gap between the second lens group and the third lens group is moved in the enlargement direction to perform focus matching adjustment. Yes.

In the zoom lens barrel unit according to the present invention, the optical system includes the first lens group having a negative focal length, the second lens group having a positive focal length, and the negative focal length. It consists of a third lens group and a fourth lens group having a positive focal length. The first lens group and the fourth lens group are fixed, and the second lens group and the third lens group rotate in the optical axis direction. It is characterized by being configured to move straight ahead while moving.
The zoom lens barrel unit according to the present invention described in claim 3 includes the one drive motor and a reduction gear train for rotationally driving the rotation drive ring,
A white plate and a photo sensor for detecting a position signal disposed on a part of the screw of the second group moving frame;
A friction piece having elasticity to impart a slight frictional force to the second group moving frame;
At the same time that the rotary drive ring is rotatably fitted, the fixed frame in which the one drive motor and the gear train are disposed,
The main group in which the second group moving frame and the third group moving frame are housed, and an inner helicoid screw is formed on an inner wall portion to be engaged with an outer helicoid screw formed on the second group moving frame and the third group moving frame, respectively. It is characterized by comprising a lens barrel.

The zoom lens barrel unit according to the fourth aspect of the present invention is configured so that at least when the second group moving frame and the third group moving frame integrally move from the wide-angle optical system region to the telephoto optical system region in a straight line. In order to ensure an air space between the second lens group and the third lens group, which is essential in zooming and focusing adjustment, contact in the rotational direction between the second group moving frame and the third group moving frame. It is characterized in that a certain gap is given to the part.
In the zoom lens barrel unit according to the fifth aspect of the present invention, in the zooming operation, the second group moving frame and the third group moving frame rotate integrally from the wide-angle optical system region to the telephoto optical system region direction. When moving straight, or when moving in a straight line from the telephoto optical system region toward the wide-angle optical system region, the air distance between the second lens group and the third lens group is the wide-angle optical system region of the optical system. To the telephoto optical system region, it is present on the infinite side in the focus matching adjustment or on the close side in the focus matching adjustment.

In the zoom lens barrel unit according to the sixth aspect of the present invention, the zoom lens barrel unit includes the second group moving frame and the third group moving frame in a range from a wide-angle optical system region to a telephoto optical system region in accordance with a zooming operation. When the second lens unit and the third lens unit move together in the direction in which the air space decreases, the second group moving frame or the third group moving frame is used during the focus matching adjustment. One of the two groups moving frame or the third group moving frame moves in the direction in which the air gap between the second lens group and the third lens group increases, that is, from the infinity side to the closest side while the other one is stationary. ,
On the other hand, with the zooming operation opposite to the above, within the range from the wide-angle optical system region to the telephoto optical system region, the second group moving frame and the third group moving frame are the second lens group and the third lens unit. When the lens unit moves integrally in a straight line in the direction in which the air interval increases, and when adjusting the focus matching, either the second group moving frame or the third group moving frame is stationary and the other of the second group moving frame is stationary. The second group moving frame or the third group moving frame moves in the direction in which the air space between the second lens group and the third lens group is reduced, that is, in the infinite direction from the closest side.

According to a seventh aspect of the present invention, the zoom lens barrel unit includes a cylindrical ring portion disposed in a part of the second group moving frame and a cylindrical ring portion disposed in a part of the third group moving frame. It is characterized by fitting so as to be capable of dynamic rotation and linear movement.
The zoom lens barrel unit according to the present invention described in claim 8 is configured such that the second lens group and the zoom lens barrel unit are coupled with the second lens group in association with the zooming operation by the rotation drive ring that rotates in one direction in conjunction with the one drive motor. When the air interval of the third lens group is expanded to a predetermined interval, the second lens group and the third lens are rotated by rotating the rotary drive ring in conjunction with the drive motor in the opposite direction. While adjusting the focus matching by moving the group air spacing in the reduction direction,
When the air gap between the second lens group and the third lens group is reduced to a predetermined interval in accordance with the zooming operation by the rotary drive ring rotating in the other direction of the one drive motor, the drive is performed. In this case, the motor is rotated in the opposite direction to move the air gap between the second lens unit and the third lens unit in the enlargement direction, thereby adjusting the focus.

The zoom lens barrel unit according to the ninth aspect of the present invention includes the third group that supports the third lens group and the outer helicoid screw of the second group moving frame that supports the second lens group at the time of zooming. The outer helicoid screw of the moving frame is integrally rotated linearly while being jointly screwed with the inner helicoid screw of the main barrel, and during the focus adjustment, the second group moving frame and the third group moving frame are temporarily engaged. The second lens group is configured such that the third lens group can be moved only in the rectilinear direction while being stationary.
In the zoom lens barrel unit according to the present invention described in claim 10, a through hole is formed in the outer wall portion of the main barrel at a position corresponding to an inner helicoid valley portion of the main barrel, The reflection type photosensor capable of detecting a change in the amount of reflected light of the projection light beam is disposed in correspondence with the through hole portion, and a white paint or a white seal for position signal detection is provided on the second group moving frame. The outer helicoid screw is characterized in that it is applied or stuck to a part of the top of the mountain that has been cut into a planar shape.

In the zoom lens barrel unit according to the eleventh aspect of the present invention, the drive ring can be rotated 360 ° or more in the forward and reverse directions with power from the drive motor unit, and is arranged in parallel with the optical axis. The provided guide shaft is fitted into a rectangular hole formed in the third group moving frame, and is driven to rotate integrally while sliding the third group moving frame in the optical axis direction. Yes.
The zoom lens barrel unit according to the present invention described in claim 12 is arranged in a state of protruding from a trough surface of the outer helicoid from a rectangular hole formed in a side wall portion of the outer helicoid of the second group moving frame. The friction piece having the elastic characteristics is accommodated in the second group moving frame, and the arc-shaped protrusion arranged at the center of the friction piece is always in contact with the inner helicoid peak of the main barrel. By sliding, a frictional force is applied to the second group moving frame.
An image pickup apparatus according to a thirteenth aspect of the present invention is characterized in that the zoom lens barrel unit according to any one of the first to twelfth aspects is mounted as a zoom lens barrel for image pickup.

The camera according to the fourteenth aspect of the present invention is characterized in that the zoom lens according to any one of the first to twelfth aspects is mounted as an imaging zoom lens barrel.
According to a fifteenth aspect of the present invention, a portable information terminal device includes the zoom lens barrel unit according to any one of the first to twelfth aspects as a zoom lens barrel of an imaging function unit. It is characterized by that.
A mobile phone according to a sixteenth aspect of the present invention is characterized in that the zoom lens barrel unit according to any one of the first to twelfth aspects is mounted on an imaging function unit.

[Action]
In order to solve the above-described problems of the prior art, the present invention includes a first lens group which is one of the photographic optical systems and is located on the most object side of the main barrel and fixed on the optical axis. An optical system is configured by a second lens group, a third lens group (and a fourth lens group fixed to a fixed frame, if necessary) arranged in the main barrel and moving linearly on the optical axis. And a helicoid screw formed on the outer periphery of each of the second group moving frame for holding the second lens group and the third group moving frame for holding the third lens group. It is formed on the inner wall portion, and moves in a straight line while rotating on the optical axis by jointly engaging with a helicoid screw having a predetermined gradient.
At the time of zooming, the second group moving frame that holds the second lens group and the third group moving frame that holds the third lens group integrally move linearly in the optical axis direction while rotating. At the time of focus matching adjustment, only the third group moving frame rotates in the direction opposite to the rotation direction at the time of zooming, so that the engagement with the second group moving frame is temporarily released, and the second group moving frame is at the current position. While moving still, only the third group moving frame rotates and moves straight. As a result, the air gap between the second lens group and the third lens group changes in the optical axis direction, so that focus adjustment can be performed.

  However, as another embodiment of the present invention different from the above, as opposed to the optical system described above, at the time of zooming, the second group moving frame and the third group moving frame are integrally rotated while rotating the optical axis. Rotate straight in the direction, but when adjusting the focus, the engagement with the third group moving frame is temporarily released, the third group moving frame remains stationary at the current position, and only the second group moving frame rotates while moving straight By moving, the air gap between the second lens group and the third lens group changes in the optical axis direction, so that it is possible to perform focus matching adjustment. Thus, the master-slave relationship of the optical system of the second lens group and the third lens group is converted, that is, even if one of the second group moving frame and the third group moving frame is stationary and the other is moved, it is equivalent. It is possible to obtain an effect. However, in the embodiment of the present invention, a description will be given with a method in which the second group moving frame is kept stationary during focus matching adjustment, and only the third group moving frame is rotated and moved straight forward.

  In the linkage relationship between the second group moving frame that holds the second lens group and the third group moving frame that holds the third lens group, a predetermined gap (play) is provided in the rotation direction along the circumferential portion. As a result, even if the third group moving frame starts to rotate, a rotation delay occurs in the second group moving frame by the determined gap. For example, when the second lens group and the third lens group move in the direction of the subject from the image sensor surface side, the direction in which the air distance between the second lens group and the third lens group decreases, that is, the third lens group is the first lens group. Since the two lens groups are moved close to each other, the focus position moves from the closest side to the infinite side in the photographing optical system. On the other hand, when the second lens group and the third lens group move by changing magnification while moving from the subject side to the imaging element surface side, the air gap between the second lens group and the third lens group increases, that is, the photographing optical system. In the system, the focal position moves from the infinite subject side to the closest side.

The fixed frame is fitted with a rotation drive ring for moving the third group moving frame in a straight line. A gear is formed on the outer peripheral portion of the rotation drive ring, and rotation of 360 ° or more is possible by rotation power from a drive motor disposed in the zoom lens barrel unit.
In addition, two guide shafts are installed in the through hole of the rotary drive ring symmetrically with respect to the center and parallel to the optical axis, and pass through the two rectangular holes drilled in the third group moving frame. And are slidably fitted. As a result, with the rotation of the rotary drive ring, the third group moving frame can move straight while rotating in the optical axis direction.
The second lens group and the third group held in the second group moving frame are slidably fitted with each other so that the cylindrical rib disposed on the second group moving frame and the cylindrical rib of the third group moving frame are slidably fitted. The optical axis of the third lens group held on the moving frame coincides with high accuracy and can be expected to prevent decentration and tilt, which are likely to occur during rotation driving, and within a predetermined rotation angle range. In FIG. 4, the rotary slide is arranged.

In order to satisfy the above conditions, the second group moving frame is provided with a convex arc-shaped rib for limiting the rotation angle in a bifurcated shape, and the third group moving frame has a convex arc shape of the second group moving frame. Convex rectangular locking ribs for restricting rotation of the ribs are provided. A predetermined fixed gap (play) is provided between the convex arc-shaped rib of the second group moving frame and the convex rectangular locking rib of the third group moving frame. As a result, even when the third group moving frame starts to rotate, the synchronous rotation of the second group moving frame is delayed by the gap.
Furthermore, after the engagement relationship with the third group moving frame is temporarily released, in order to prevent the second group moving frame itself in a stationary state from causing a positional deviation due to vibration or the like, two A friction piece formed of plastic having a generating characteristic is built in a symmetrical position with respect to the center, and the tip arc portion of the friction piece rotates and moves while always in contact with the peak of the inner helicoid screw of the main barrel.
As a result, even when the engagement with the third group moving frame is released, the second group moving frame itself can remain stationary at the same position without causing positional displacement due to vibration or the like.

In the zoom lens barrel unit, a drive motor and a reduction gear train for rotating the rotary drive ring are arranged at the optimum positions.
Further, a rectangular hole is formed at a predetermined position of a valley of a helicoid screw disposed on the inner wall of the main barrel.
A reflection type photosensor for detecting a reflected signal of light is attached to the outer wall portion of the main barrel corresponding to the rectangular hole, and is fixedly bonded.
A white concave plate having a good reflection efficiency is formed by forming a slight recess in a part of the top of the crest of the helicoid screw of the second group moving frame formed of black plastic in advance. A white seal is stuck or a white paint is applied.
As a result, when the boundary portion of the white reflecting plate on the second group moving frame passes through the rectangular hole of the main barrel, a change occurs in the amount of reflected light of the light projected from the reflective photosensor. It is possible to detect the position of the group movement frame.
An image sensor unit for converting the light from the subject (object) through the imaging optical system into an electrical signal and displaying the captured image on the monitor screen after image processing is located at the bottom of the fixed frame. It is arranged and fixed to.

According to the present invention, the second group moving frame and the third group moving frame are jointly screwed into the main lens barrel to realize a single layer of the lens barrel structure, and can be continuously driven only by a single drive motor. The zoom lens barrel unit can be reduced in size and weight, the number of parts can be reduced, the cumulative error of parts can be reduced, and the assembly time can be achieved. It is possible to provide a zoom lens barrel unit that can realize a shortening of the zoom lens barrel.
Furthermore, by mounting the zoom lens barrel according to the present invention, it is possible to reduce the size and weight of the lens itself, to reduce the number of parts, and to reduce the cumulative error of parts, while also providing a zoom ratio that excels in operability. An imaging device, a camera, a portable information terminal device, and a mobile phone that have both the function and the focus adjustment function can be provided at low cost.

DESCRIPTION OF EMBODIMENTS Hereinafter, a description will be given with reference to the accompanying drawings according to an embodiment of the present invention.
However, regarding the components (or components), shapes, and other arrangements cited and described in the present embodiment, the scope of the present invention is not limited unless otherwise specified, and is merely an illustrative example. There is only.
FIG. 1 is an exploded perspective view of a zoom lens barrel unit according to the present invention as seen from the upper right side of the front side. FIG. 2 is a partially omitted view of the zoom lens barrel unit in FIG. It is a perspective view which expands and shows the external appearance structure which looked at the part from front side diagonally upward. 3 and 4 are longitudinal sectional views of the configuration of the zoom lens barrel unit shown in FIG. 1 cut at a substantially central portion, and FIG. 11 is a part of FIGS. 3 and 4 omitted. It is a longitudinal cross-sectional view shown.
An embodiment of the present invention will be described in detail with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

As shown in FIG. 1, the zoom lens barrel unit of the present invention includes a lens 11 a constituting the first lens group 11 and a decorative plate 12 for shielding unnecessary rays around the lens. As shown in FIG. 3, an inner helicoid screw 10 c is formed on the inner periphery of the main barrel 10.
As shown in FIGS. 1, 2, and 11, the two-group moving frame 20 in which the outer helicoid screw 20 a is formed on the outer peripheral portion is provided with friction pieces 22 having elasticity to impart a frictional force at both end portions. 22b is stored while being held by the groove 20h of the second group moving frame 20, and at the same time, the friction piece 22 is inserted into the rectangular long hole 20b formed in the valley of the helicoid screw 20a of the second group moving frame 20. A tip arc portion 22a is inserted. At this time, the arcuate portion 22a of the friction piece 22 is disposed in a state of slightly protruding from the bottom of the valley of the helicoid screw 20a of the second group moving frame 20. Further, the friction piece 22 is thin-walled with a black plastic resin so as to have a resilience characteristic.
As a result, the tip arc portion 22a of the friction piece 22 and the crest portion 10d of the inner helicoid screw 10c of the inner barrel 10 come into contact with each other, and an external force is applied. The frame 20 itself can remain stationary at the same position without causing positional displacement due to vibration or the like.

Further, the lens 21a, the lens 21b, and the lens diaphragm 21c constituting the second lens group 21 are housed and fixedly supported (mounted) in the second group moving frame 20 so that their centers coincide with the optical axis.
Further, the third group moving frame 30 having the outer helicoid screw 30a on the outer peripheral portion is stored and fixed so that the centers of the lens 31a and the lens diaphragm 31b constituting the third lens group 31 coincide with the optical axis.
The outer helicoid screw 20a of the second group moving frame 20 and the outer helicoid screw 30a of the third group moving frame 30 having the same screw pitch and mountain shape are shared with the inner helicoid screw 10c formed on the inner peripheral portion of the main barrel 10. It is configured to move in a straight line while being screwed together.

As shown in FIG. 11, the cylindrical rib 20j of the second group moving frame 20 and the cylindrical rib 30e of the third group moving frame 30 are slidably fitted with high precision so that the second group moving frame 20 is held by the second group moving frame 20. The optical axes of the second lens group 21 and the third lens group 31 held by the third group moving frame 30 can be accurately matched, and the effect of preventing eccentricity and inclination that is likely to occur during rotation driving is achieved. can get. The second group moving frame 20 and the third group moving frame 30 are configured to be slidable within a predetermined rotation angle range.
In the main barrel 10, a rotation driving ring 50 for rotating the third group moving frame 30 is rotatably fitted to the fixed frame 80.
Further, two guide shafts 51 are implanted and fixed in parallel to the optical axis in the through holes 50a symmetrically arranged at the center of the rotation drive ring 50, and the guide shafts 51 are arranged in a three-group moving frame as shown in FIG. The third group moving frame 30 is integrally rotated in the circumferential direction and slidably fitted in the axial direction.

Further, the center of the lens 40a constituting the fourth lens group 40 is fixed at an appropriate position on the optical axis of the fixed frame 80, and at the same time, the gear train 60 (gear 60a, gear 60b, gear) constituting the speed reduction unit mechanism. 60c) is rotatably fitted in the gear shaft 52 planted in the fixed frame 80 and the boss 10e disposed in the main barrel 10.
A pinion gear 71 is press-fitted and fixed to the rotation shaft of the drive motor 70 constituting the speed reduction mechanism. The drive motor 70 is inserted into a cylinder 10a attached to the side portion of the main lens barrel 10, and then fixed by positioning and fixing.
The positioning hole (not shown) of the main barrel 10 and the positioning boss 80a of the fixed frame 80 are fitted to each other, and the rectangular hole 10b formed in the side wall portion of the main barrel 10 and the side surface of the fixed frame 80 are arranged. The hook nail | claw part 80b provided will be in a latching state, and will be fixed.
Finally, the set screw 81 is fitted into the through hole 80 c of the fixed frame 80 and is locked by the screw hole of the main barrel 10.
As a result, the main barrel 10 and the fixed frame 80 are integrated.
In this way, a single layer of the lens barrel is realized.

On the optical axis of the photographing lens system on the focal plane side of the fixed frame 80, an image sensor unit 90 equipped with a CCD, a CMOS sensor, or the like is disposed, and the center of the light receiving surface of the image sensor 90a coincides with the optical axis. Properly arranged.
The photographing optical system will be described with reference to the external exploded perspective view of FIG. 1 and the central sectional view of the zoom lens barrel unit of FIG.
Regarding the configuration of the photographic optical system in the present invention, from the subject side, the lens 11a constituting the first lens group 11 is a negative lens having a negative focal length, and is fixed on the optical axis of the main barrel 10.
The lens 21a and the lens 21b constituting the second lens group 21 are positive lenses having a positive focal length as a composite lens system, and move linearly while rotating in the optical axis direction in accordance with the zooming operation. The lens 31a constituting the third lens group 31 is a negative lens having a negative focal length, and moves together with the second lens group 21 while rotating in the optical axis direction integrally with the zooming operation. At the time of focus matching adjustment, the second lens group 21 is kept in a stationary state and is driven only by the rotationally straight drive of the third lens group.
The lens 40a constituting the fourth lens group 40 is a positive lens having a positive focal length, and is fixed on the optical axis of the fixed frame 80 to constitute a photographing optical system.

In the wide-angle optical system, the zoom optical system has a structure in which the first lens group 11 is set to a negative focal length in order to guarantee a wide angle of view, and an image surface on the wide-angle side and negative distortion aberration performance are improved. It is designed for the purpose of making the outer diameter of the lens 11a as small as possible.
The second lens group 21 constitutes an optical system of a positive lens for the purpose of correcting chromatic aberration and spherical aberration by two lenses 21a and 21b having a positive focal length and a negative focal length. While the second lens group 21 and the third lens group 31 are rotated and linearly moved integrally along the optical axis, the zooming function and the correction (compensator) function are compensated, and a focus matching adjustment function is further provided. .
The zoom optical system configuration is completed by forming a pair of movable lens groups by moving the second lens group 21 and the third lens group 31 with the air gap as close as possible.

The fourth lens group has a function of suppressing an increase in incident angle of the chief ray to the image sensor 90a, in particular, an incident angle on the wide angle side, and also serves to suppress an increase in positive distortion on the telephoto side. ing.
In the embodiment of the present invention, the fourth lens group is adopted. However, when a lens system configuration with a long overall length is allowed, even when the incident angle to the image sensor 90a is somewhat relaxed, or For example, when the back focus is long, the fourth lens group can be omitted. As a result, the optical system can be configured with only the first lens group, the second lens group, and the third lens group.
In the optical system configuration of the present embodiment, the second lens group 21 and the third lens group 31 are moved integrally along the optical axis while referring to the central sectional view of the zoom lens barrel unit of FIGS. A detailed explanation will be given of the zooming function and the correction function at the time.
As the photographing optical system, FIG. 3 is a diagram showing a wide-angle photographing optical system position, and FIG. 4 is a diagram showing a telephoto photographing optical system position.

At the time of zooming in the general photographing optical system, the second lens group 21 and the third lens group 31 at the wide-angle optical system position in FIG. 3 are in the telephoto photographing optical system position direction in FIG. Moving. A function for always correcting the air gap between the second lens group 21 and the third lens group 31 is necessary so that a specific finite subject always focuses on the imaging surface during zooming movement.
In general, in zooming movement from the wide-angle position to the telephoto position, the air distance between the second lens group 21 and the third lens group 31 is the same at the wide-angle position and the telephoto position regardless of the infinite distance or the finite distance. It spreads and approaches in the middle position.
When the positions are connected, a so-called U-shaped curve shown in FIG. 12 is formed.
The U-shaped curve of the air gap between the second lens group 21 and the third lens group 31 described above will be described in detail with reference to FIGS.

FIG. 11 is a diagram showing a state in which the second group moving frame 20 holding the second lens group 21 and the third group moving frame 30 holding the third lens group 31 are closest to each other.
In the optical system, the minimum air gap position at this time is substantially at the intermediate optical system position. FIG. 12 is a diagram showing the amount of change in the air separation distance between the second lens group 21 and the third lens group 31 at the positions of the wide-angle optical system, the intermediate optical system, and the telephoto optical system. For convenience, the second lens group 21 is shown. It is a positional relationship figure in the state which fixed. A curve P indicates a line connecting the change movement positions of the third lens group 31 when the photographing optical system at the wide angle, intermediate, and telephoto positions is focused on a subject at an infinite position.
Here, W (∞) is the infinite focus position in the wide-angle optical system, N (∞) is the infinite focus position in the infinite optical system, and T (∞) ) Means that the focal length is at an infinite position in the telephoto optical system.

A curve Q indicates a state where the movement change position of the third lens group 31 is connected when the photographing optical system is focused on a subject at a close distance at each of the wide-angle optical system, the intermediate optical system, and the telephoto optical system position. ing. Here, W1 is the focal distance of the subject at the closest position in the wide-angle optical system, N1 is the focal distance at the closest position in the substantially intermediate optical system, and T1 is the closest focal distance in the telephoto optical system. It means to exist in position.
As can be understood from the above description, the minimum value of the air separation distance between the second lens group 21 and the third lens group 31 is a substantially intermediate optical system position of the photographing optical system, and the focus matching position is an infinite distance. Become.
Similarly, the maximum value of the air separation distance between the second lens group 21 and the third lens group 31 is when the photographing optical system is the wide-angle optical system position or the telephoto optical system position, and the focus matching position is the close distance.

As a result of the above, regarding the moving range from the minimum amount to the maximum amount of the air gap between the second lens group 21 and the third lens group 31 in zooming from the wide-angle optical system to the telephoto optical system, the position of the minimum amount is the photographing optical system. When the focus matching position is at an infinite distance, the maximum amount is the wide-angle optical system position or the telephoto optical system position of the photographing optical system, and the focus matching position is at a close distance.
As a result, if at least the moving distance from the minimum amount to the maximum amount in which the air gap distance between the second lens group 21 and the third lens group 31 changes can be compensated, it is possible to perform focus adjustment adjustment in the entire zoom range.
At the time of focus adjustment, the engagement between the second group moving frame 20 and the third group moving frame 30 is temporarily released, and the second lens group 21 remains stationary and only the third lens group 31 moves in a straight line. Done. At this time, when the shooting subject distance moves from an infinite distance to a close distance, the third lens group 31 moves in a straight line from the subject side to the imaging surface side, that is, the second lens group 21 and the third lens group 31. Focus adjustment is performed while the air interval of the air is widened.

On the other hand, when the shooting subject distance moves from a close distance to an infinite distance, the third lens group 31 moves straight from the imaging surface side to the subject side, that is, the second lens group 21 and the third lens group 31. Focus adjustment is performed while approaching.
Next, a series of operations when the power from the drive motor 70 is transmitted to the third group moving frame 30 and the second group moving frame 20 via the speed reduction mechanism will be described with reference to FIGS. .
The rotational force from the pinion gear 71 press-fitted into the drive motor 70 is decelerated sequentially through the gear 60a, gear 60b, and gear 60c that constitute the gear train 60, and is fitted into the fixed frame 80. Between the fixed frame 80 and the rotation drive ring 50 which is rotatably arranged and has a gear 50b formed on the outer periphery.
In the rotary drive ring 50, two guide shafts 51 are appropriately planted so as to be parallel to the optical axis in a through hole 50a disposed at a symmetrical position with respect to the center.

5, 6, 7, and 8 are simplified for easy understanding and explanation of the related operations of the second group moving frame 20, the third group moving frame 30, and the guide shaft 51. 5 and 7 are front views, FIG. 6 is a rear view, and FIG. 8 is a plan view.
FIGS. 9 and 10 are simplified front views for explaining the relationship between the second group moving frame 20 and the friction piece 22.
FIG. 5 is a front view of the third group moving frame 30 as viewed from the subject side, and the hatched portion at the center is a simplified representation of the third lens group 31 mounted on the third group moving frame 30.
A guide shaft 51 passing through a rectangular long hole 30b arranged symmetrically with respect to the center of the third group moving frame 30 forms a fitting state while contacting the circumferential (rotating) direction. Further, convex rectangular locking ribs 30c are arranged symmetrically with respect to the center on the surface portion.

FIG. 6 is a rear view of the second group moving frame 20 as viewed from the image sensor 90a surface side, and the hatched portion at the center indicates the second lens group 21. FIG.
The fan-shaped elongated hole 20f is arranged at the left and right positions with respect to the center, and even if the guide shaft 51 that always rotates integrally with the third group moving frame 30 rotates clockwise or counterclockwise, it contacts the second group moving frame 20. It is configured to be drilled in a shape that does not occur. Further, convex arc-shaped ribs 20c and 20d are disposed diagonally with respect to the center on the surface portion.
FIG. 7 shows the second group moving frame 20 in FIG. 6 inverted and overlapped with the optical axis position of the third group moving frame 30 in FIG. It is the front view which looked at the combined state from the to-be-photographed object side.
FIG. 8 shows a state in which the second group moving frame 20, the third group moving frame 30, the guide shaft 51, and the rotation drive ring 50 of FIG. It is a bottom view.

The operation of the zoom lens barrel unit will be described with reference to FIG. 5, FIG. 6, FIG. 7, and FIG.
In FIG. 7, when the rotational drive ring 50 is rotationally driven counterclockwise (assumed to be set to the right helicoid screw) as viewed from the subject side, the guide shaft 51 implanted integrally with the rotational drive ring 50 is The three-group moving frame 30 integrally rotates counterclockwise while slidingly engaging with the rectangular long hole 30b. While maintaining the stationary state of the second group moving frame 20 at first, between the end face 30c1 of the rectangular locking rib 30c of the third group moving frame 30 and the tip 20c1 of the arc-shaped rib 20c arranged in the second group moving frame, As shown in FIG. 7, since there is an angular gap corresponding to G1, even if the temporary and third-group moving frame 30 rotate counterclockwise, an angular gap equivalent to G1 will occur. .
That is, when the end face 30c1 of the rectangular locking rib 30c of the third group moving frame 30 and the tip 20c1 of the arc-shaped rib 20c of the second group moving frame 20 are engaged, the second moving frame 20 and the third group moving frame 30 are integrated. Thus, the rotation straight movement is started counterclockwise. At this time, it means that the air distance between the second lens group 21 and the third lens group 31 is set to the closest distance.

  Contrary to the above, when the rotary drive ring 50 is driven to rotate clockwise as viewed from the subject side, the guide shaft 51 and the third group moving frame 30 (assumed to be set to the right helicoid screw) rotate integrally clockwise. To do. At this time, a portion corresponding to the G2 angle is formed between the end face 30c2 of the rectangular locking rib 30c of the third group moving frame and the tip 20d1 of the arc-shaped rib 20d arranged on the second group moving frame (assumed to be set to the right helicoid screw). Since there is a gap, even if the provisional third group moving frame 30 rotates in the clockwise direction, a gap engagement deviation corresponding to the G2 angle occurs. That is, when the end surface 30c2 of the rectangular locking rib 30c of the third group moving frame and the tip 20d1 of the arc-shaped rib 20d of the second group moving frame are engaged, the second moving frame 20 and the third group moving frame 30 are integrated. Starts straight rotation in the clockwise direction. This starting position means that the air distance between the second lens group and the third lens group is set to the maximum separation distance.

Here, the set minimum proximity value of the air gap distance between the second lens group 21 and the third lens group 31 is an infinite distance of the subject (can be set arbitrarily) from the wide-angle optical system to the telephoto optical system in the zooming range. Adopt minimum interval value.
Further, the maximum separation value of the air gap between the second lens group 21 and the third lens group 31 employs the maximum gap value from the wide-angle optical system in the zooming range to the close distance (can be arbitrarily set) of the subject in the telephoto optical system.
As a result of the above, when the third group moving frame 30 rotates counterclockwise, that is, in zooming from the wide-angle optical system to the telephoto optical system, the air interval between the second lens group 21 and the third lens group 31 is While keeping the minimum interval value, the second group moving frame 20 and the second group moving frame 20 move in a straight line.
As a result, in the focus matching adjustment, after the zooming operation is completed, only the third group moving frame 30 is rotated in the clockwise direction while the second group moving frame 20 is temporarily stopped at the current state. Rotational rectilinear movement starts in the direction in which the air space between the group 21 and the third lens group 31 increases, that is, the focus adjustment of the subject is performed while moving from the infinite distance side to the closest distance side.

  Contrary to the above, the setting of the maximum distance value of the air distance between the second lens group 21 and the third lens group 31 is performed in the movement from the telephoto optical system position to the wide-angle optical system position in the zooming range. The maximum distance value of the air distance on the closest distance side when adjusting the focus matching of the optical system or the wide-angle optical system is adopted. As a result of the above, when the third group moving frame 30 rotates clockwise, that is, in zooming from the telephoto optical system position to the wide-angle optical system position direction, the air interval between the second lens group 21 and the third lens group 31 is While maintaining the maximum interval value, the second group moving frame 20 and the third group moving frame 30 integrally rotate and move linearly. As a result, in the focus matching adjustment, after the zooming is completed, only the third group moving frame 30 rotates counterclockwise while the second group moving frame 20 is temporarily stopped at the current state, so that the second lens group The rectilinear movement starts in the direction in which the air space between the lens 21 and the third lens group 31 decreases. That is, the focus matching adjustment is performed while moving from the closest distance side of the subject toward the infinite distance side.

Here, another embodiment (second embodiment) opposite to one embodiment (first embodiment) of the above-described invention will be described (not shown).
In the embodiment of the present invention, the second lens group 21 and the third lens group 31 move straight in the optical axis direction while rotating integrally, thereby achieving a zooming function and the third lens group 31. However, by rotating in the direction opposite to the rotation direction, the engagement with the second lens group 21 is temporarily released, and the second lens group 21 remains temporarily stationary. And the third lens group 31 change in the direction of the optical axis, thereby adjusting the focus.

  However, contrary to the above configuration, the same result can be obtained by reversing the master-slave relationship of the optical system of the second lens group and the third lens group, that is, by switching the role functions of the second group moving frame and the third group moving frame. It is possible to obtain That is, in zooming, the second lens group and the third lens group move in a straight line in the direction of the optical axis while integrally rotating, but, contrary to the above, It is also possible to perform the focus matching adjustment by temporarily placing the second lens group in a stationary state and rotating only the second lens group in the direction opposite to the rotation.

When the roles of the second group moving frame and the third group moving frame shown in the first embodiment are exchanged, that is, the guide shaft installed in the rotation drive ring is arranged symmetrically with respect to the center of the second group moving frame. The rotary drive ring and the second group moving frame are driven to rotate linearly integrally while penetrating through the rectangular oblong hole and forming a fitting state while being in contact with the circumferential direction. At this time, the third group moving frame is provided with a rotation angle limiting rib, and the second group moving frame is provided with a locking rib for locking the rotation angle limiting rib of the third group moving frame. A gap (play) having a predetermined angle is provided between the third group moving frames as the second group moving frames are rotated. As a result, even if the second group moving frame starts to rotate, the synchronous rotation of the third group moving frame is delayed by the gap.
For example, when the second lens group and the third lens group move in the direction of separation from the image sensor side, that is, the air gap between the second lens group and the third lens group is increased. At this time, since the second lens group moves away from the subject side, the subject distance moves to the near side. On the other hand, when the second lens group and the third lens group move with magnification while moving close to the image sensor, the direction in which the air distance between the second lens group and the third lens group decreases, that is, As a result of the proximity of the second lens group and the third lens group, the subject distance moves to the infinite side.

In addition, fan-shaped long holes are arranged in the left and right positions with respect to the center of the third group moving frame, and even if the guide shaft that always rotates integrally with the provisional second group moving frame rotates clockwise or counterclockwise, the third group moving frame It is configured to have a shape that does not contact the moving frame. In addition, in the third group moving frame, elastic friction pieces for applying a friction force are stored in a state where both end portions are held between the grooves of the third group moving frame. The tip arc portion of the friction piece is inserted into a rectangular long hole formed in the valley of the helicoid screw of the group moving frame. At this time, the tip arc portion of the friction piece is arranged in a state of slightly protruding from the bottom surface of the valley of the helicoid screw of the third group moving frame. In addition, the friction piece is thin-walled with a plastic resin so as to have elasticity.
As a result, when the tip arc portion of the friction piece and the peak portion of the inner helicoid screw of the main barrel come into contact with each other, the ball is repelled and a frictional force is generated. As a result, the third group moving frame itself can stay at the same position while temporarily stopping without causing a positional shift due to vibration or the like.
In this way, it can be understood that zooming and focus matching adjustment are possible even if the roles of the second group moving frame and the third group moving frame are interchanged.

Here, it should be noted that only one drive motor can be used to change the magnification by integral rotation and linear movement of the second group moving frame and the third group moving frame, and the second group moving frame and the third group moving frame. Is temporarily disengaged and either one of the second group moving frame or the third group moving frame is rotated and moved in a straight line, thereby enabling the focus matching adjustment.
The configuration and operation of the second group moving frame 20 and the friction piece 22 will be described with reference to FIGS.
As described above, a rectangular hole is formed in the valley of the helicoid screw 20a of the second group moving frame 20 in order to prevent the second lens group 21 from being displaced due to a slight external force or vibration during focus matching adjustment. 20b is drilled in a symmetrical position with respect to the center, and the arcuate portion 22a of the friction piece 22 formed of a resilient plastic material is formed in the rectangular hole 20b, and the outer helicoid screw 20a of the second group moving frame 20 is formed. The second group moving frame 20 is housed in a state of projecting outward from the trough portion 20k and can contact the peak portion 10d of the inner helicoid screw 10c of the main barrel 10 to obtain an appropriate frictional force. It is arranged in the inside.

In the embodiment of the present invention, the friction piece 22 formed of a plastic material having elasticity is used. However, it is possible to satisfy the configuration condition even with a coil spring or a leaf spring having elasticity. It is.
As shown in FIGS. 1, 2, and 4, a side wall window 10 f is formed in the side wall portion of the main lens barrel 10 at a portion corresponding to the valley of the inner helicoid screw 10 c of the main lens barrel 10. A notch 20g (FIG. 2) in which a part of the outer helicoid screw 20a of the group moving frame 20 is deleted from the center with the same radius is disposed, and the notch 20g has a white plate or A white portion 20e of a white seal (or a surface portion to which a white paint is applied) is disposed.
At this time, the entire second group moving frame 20 is formed of black plastic.

Further, the side wall window 10f of the main lens barrel 10 is a generally well-known technique. By projecting a light beam and detecting infrared light reflected by the object, the position of the movable object is detected. A reflective photosensor 13 capable of detection is mounted, and the periphery is fixed with an adhesive.
As a result, when the white portion 20e applied to the helicoid mountain 20a of the second group moving frame 20 passes through the side wall window 10f of the main barrel 10, the infrared rays projected from the reflective photosensor 13 are second group. Reflection at the boundary between the black portion and the white portion 20e of the helicoid mountain 20a of the moving frame 20 causes a change in the reflectance of the light beam. As a result, the determined position of the second group moving frame 20 is detected appropriately. can do.

Next, the contents will be described with reference to FIG.
The hatched portion of the rectangular figure is a figure showing the white portion 20e. In a normal zooming operation, the A portion indicates the telephoto end position, the B portion indicates the wide angle end position, and the A 'portion includes two groups. It is a movement end position on the telephoto optical system side of the moving frame 20, and is an unnecessary part in normal operation.
For example, it is a position where the driving is forcibly stopped when an abnormality occurs in a circuit or a mechanism during the driving rotation operation.
Similarly, B ′ is a movement end position on the wide-angle optical system side of the second group moving frame 20 and is an unnecessary part in normal operation.
Similarly, this is a position for forcibly stopping when an abnormality occurs in the circuit or mechanism during the driving rotation operation.
The end portion 20e1 of the white portion 20e is a reset signal detection position for position detection when the second group moving frame 20 moves straight forward from the telephoto optical system side to the wide-angle optical system side, and continues after the position detection. When the second group moving frame 20 continues to move linearly, the motor is driven with a count pulse determined in advance on the circuit, and then stops at the wide-angle end B.

On the other hand, the rotation signal of the second group moving frame 20 is started from the wide-angle end B, and the position of the second group moving frame 20 is detected along with the movement toward the telephoto optical system. When the straight rotation is continued, the telephoto end A becomes the maximum moving distance and stops. As described above, the reset signal detection is used for confirming the zooming position of the second group moving frame 20 from the wide-angle optical system to the telephoto optical system.
FIG. 14 and FIG. 15 depict an external perspective view of a mobile phone equipped with the above-described zoom lens barrel unit according to the present invention, and the actual arrangement and the like may be different. FIG. 14 shows the wide-angle switching button 5 used in the zooming operation, and when the wide-angle switching button 5 is kept pressed, the second lens group and the third lens group integrally rotate and move in the direction of the wide-angle optical system. . On the other hand, if the telephoto switch button 6 is continuously pressed, the second lens group and the third lens group integrally move in a straight line from the wide-angle optical system direction to the telephoto optical system direction. Further, a release button 7 for taking a picture and a zoom lens barrel unit 4 according to the present invention are arranged in the main body.

  Further, a liquid crystal monitor 8 for displaying a video image that has undergone signal image processing is disposed on the lid portion 9 that is rotatably disposed by a hinge. FIG. 15 shows a state in which the cellular phone is folded, and a dust-proof glass 3 for protecting the photographing lens is fixed to the outer case 1.

The entire series of operations will be described with reference to FIGS. 1, 3, 7, 13, and 14.
For example, when the main power supply (not shown) of the zoom lens barrel unit is turned on, the zoom position of the second group moving frame 20 and the third group moving frame 30 is set at a substantially intermediate position between the wide-angle optical system and the telephoto optical system. The description starts assuming that it exists.
First, when the main power supply of the mobile phone is turned on, infrared rays are projected into the main lens barrel 10 from the reflective photosensor 13 disposed in the side wall window 10f of the main lens barrel 10, and the second group moves. The signal (presence) of the white portion 20e applied to the frame 20 is confirmed.
At present, since the second group moving frame 20 is present at a substantially intermediate position between the wide-angle optical system and the telephoto optical system, the amount of reflected light is low, that is, the LOW state as an electric signal. The rotation of the drive motor 70 is started to confirm the signal and the signal at the reset position 20e1.

Here, when the helicoid screw of the main barrel 10, the second group moving frame 20, and the third group moving frame 30 is set as a right screw, the rotational force from the drive motor 70 causes the gear 50 a and gear 50 b of the gear train 50 from the pinion gear 71. When the rotary drive ring 50 rotates clockwise (when viewed from the subject side) via the gear 50c, first, the third group moving frame 30 starts to rotate. At this time, the third group moving frame 30 is rectangular. Since there is an angular gap corresponding to G2 between the end face 30c2 of the locking rib 30c and the tip 20d1 of the arc-shaped rib 20d disposed on the second group moving frame, the temporary third group moving frame 30 rotates clockwise. However, an engagement delay corresponding to G2 occurs, and thereafter, the second group moving frame 20 integrally rotates with the third group moving frame 30 and moves linearly in the direction of the image sensor surface 90a.
As a result, the white portion 20e of the second group moving frame 20 crosses the reflective photosensor 13, and the reset signal position 20e1 is confirmed.

Subsequently, after rotating in advance for the number of steps of the drive motor 70 stored in advance in the EPROM (block wiring diagram is omitted) arranged on the circuit, the drive motor is moved to the wide-angle end position B shown in FIG. Stop. At this time, the air distance between the second lens group 21 and the third lens group 31 is at the maximum dimension value.
When shooting at the wide-angle end of this wide-angle optical system, at least the maximum movement range of the third group lens shown in FIG.
Next, when the telephoto switch button 6 arranged in FIG. 14 is kept pressed, the rotation drive ring 50 continues to rotate counterclockwise, and by releasing the finger halfway, the telephoto optical system position is changed from the wide-angle optical system position. Stop at any position in between. At this time, the air space between the second lens group 21 and the third lens group 31 is a minimum proximity value. At this time, it is at an infinite distance position of the substantially intermediate optical system.

For this reason, at the time of focus matching adjustment, the third lens group 31 is temporarily separated from the second lens group 21 by rotating the rotary drive ring 50 in the direction opposite to the rotation, that is, in the clockwise direction. Match adjustment is possible.
At this time, the focus position detects the focus matching position while changing from an infinite distance to a close distance direction, but in the same way as described above, within the maximum movement amount range of the third lens group 31 shown in FIG. Of course, if the third group moving frame 30 moves, it goes without saying that the focus matching adjustment is always possible regardless of the subject distance, regardless of the rotation direction of the rotation drive ring 50.

  The zoom lens barrel unit according to the present invention can be mounted on a barrel mechanism of a portable information terminal device such as a mobile phone or a PDA (Personal Digital Assistant), a silver salt camera, a digital camera, or the like.

It is a disassembled perspective view of the component which shows one Embodiment which concerns on the zoom lens barrel unit of this invention. FIG. 3 is an exploded perspective view in which a part of the constituent members shown in FIG. 1 is partially omitted to explain a partial positional relationship of the constituent members according to an embodiment of the zoom lens barrel unit of the present invention. In order to explain in detail an embodiment of the present invention, it is a cross-sectional view of the center part of each part constituting the zoom lens barrel unit, and shows a state in which the photographing optical system is at the wide-angle end position. FIG. 2 is a cross-sectional view of a central portion of each member constituting a zoom lens barrel unit for illustrating an embodiment of the present invention in detail, showing a state in which the photographing optical system is at a telephoto end position. FIG. 7 is a simplified front view for explaining the operation of a third group moving frame and a guide shaft constituting the zoom lens barrel unit in one embodiment of the present invention. FIG. 5 is a simplified rear view for explaining the operation of the second group moving frame and the guide shaft constituting the zoom lens barrel unit in one embodiment of the present invention. 6 is a front view of a state in which the second group moving frame of FIG. 6 constituting the zoom lens barrel unit in one embodiment of the present invention is reversed and superimposed on the front view of the third group moving frame and guide shaft of FIG. 5. FIG. 8 is a bottom view when the zoom lens barrel unit according to the embodiment of the present invention is viewed from the direction of arrow P in FIG. 7. It is a front view of the friction piece used for the zoom lens barrel unit in one embodiment of the present invention. It is a front view which shows the state which mounted the friction piece in the 2nd group moving frame which comprises the lens-barrel unit in one Embodiment of this invention, and was integrated. It is sectional drawing for demonstrating the operation | movement of the air space | interval change of the 2nd group moving frame and 3rd group moving frame of the lens-barrel unit in one Embodiment of this invention. In order to easily understand the amount of change in the air gap between the second lens group and the third lens group of the lens barrel unit in one embodiment of the present invention, each of the second group moving frame and the third group moving frame shown in FIG. It is explanatory drawing linked | related with the position. It is explanatory drawing for demonstrating the reset position signal detection in one Embodiment of this invention. 1 is an external perspective view showing a state in which a zoom lens barrel unit is built in a mobile phone in an embodiment of the present invention. 1 is an external perspective view showing a state in which a mobile phone incorporating a zoom lens barrel unit is folded in an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer case 2 Inner case 3 Dust-proof glass 4 Zoom lens barrel unit 5 Wide angle switching button 6 Telephoto switching button 7 Release button 8 Monitor 9 Lid 10 Main barrel 10a Cylindrical portion 10b Rectangular hole 10c Helicoid screw 10d Helicoid peak 10e Gear supporting boss 11 First lens group 11a Lens constituting first lens group 12 Decorative plate 13 Reflective photosensor 20 Second group moving frame 20a Second group moving frame outer helicoid screw 20b Second group moving frame side wall Rectangular long holes 20c, 20d Convex arc-shaped ribs 20c1, 20d1 Arc rib tip 20e White reflecting portion 20e1 Reset signal detection position 20f Fan-shaped long hole 20g Gear crest notch 20h Groove 20k Outer helicoid screw valley 20j 2 Cylindrical fitting portion of group moving frame 21 Second lens group 21a, 21b Second lens 21c Lens diaphragm 22 Friction piece 22a Arc end portion of friction piece 22b Both ends of friction piece 30 Third group moving frame 30a Third helicoid screw 30b Third group moving frame rectangular long hole 30c Third group moving frame Convex rectangular locking rib 30c1 Side wall surface of convex rectangular locking rib 30c2 Side wall surface of convex rectangular locking rib 30e Cylindrical fitting portion of third group moving frame 31 Third lens group 31a Construct third lens group Lens 31b Lens diaphragm 40 Fourth lens group 40a Lens constituting the fourth lens group 50 Rotation drive ring 50a Rotation drive ring through hole 50b Rotation drive ring outer peripheral gear part 51 Guide shaft 52 Gear shaft 60 Gear train 60a, 60b , 60c gear 70 drive motor 71 pinion gear 80 fixed frame 80a positioning boss 80b hook claw portion 80c through hole 81 set screw 9 Imaging device unit 90a imaging element

Claims (16)

At least a first lens group having a negative focal length, a second lens group having a positive focal length, and a third lens group having a negative focal length, wherein the first lens group is fixed, and the second lens group and the second lens group In the optical system in which the three lens groups rotate and move straight in the optical axis direction,
A second group moving frame that holds the second lens group and has an outer helicoid screw formed in the periphery;
A third group moving frame that holds the third lens group and has an outer helicoid screw formed in the periphery;
A main barrel having an inner helicoid screw formed on the inner wall so that the second group moving frame and the third group moving frame can be rotated and moved in a straight line while being screwed together;
A rotation drive ring in which either one of the second group moving frame or the third group moving frame is rotated and linearly moved, and a guide shaft is implanted and fixed in parallel with the optical axis;
A single drive motor that rotationally drives the rotary drive ring;
When the air gap distance between the second lens group and the third lens group is expanded to a predetermined interval in accordance with the zooming operation by the rotation in one direction of the rotary drive ring in conjunction with the drive motor, The drive motor is rotated in the opposite direction to adjust the focus matching by moving the air gap between the second lens group and the third lens group in the reduction direction.
When the air gap between the second lens group and the third lens group is reduced to a predetermined interval in accordance with a zooming operation by rotation in the other direction of the rotary drive ring in conjunction with the one drive motor. The drive motor is rotated in a direction opposite to the above, and the air gap between the second lens group and the third lens group is moved in the enlargement direction to perform focus matching adjustment. Zoom lens barrel unit.   The optical system includes the first lens group having a negative focal length, the second lens group having a positive focal length, the third lens group having a negative focal length, and a fourth lens group having a positive focal length. 2. The first lens group and the fourth lens group are fixed, and the second lens group and the third lens group are configured to move linearly while rotating in the optical axis direction. Zoom lens barrel unit. The one drive motor and a reduction gear train for rotationally driving the rotary drive ring;
A white plate and a photo sensor for detecting a position signal disposed on a part of the screw of the second group moving frame;
A friction piece having elasticity to impart a slight frictional force to the second group moving frame;
At the same time that the rotary drive ring is rotatably fitted, the fixed frame in which the one drive motor and the gear train are disposed,
The main group in which the second group moving frame and the third group moving frame are housed, and an inner helicoid screw is formed on an inner wall portion to be engaged with an outer helicoid screw formed on the second group moving frame and the third group moving frame, respectively. The zoom lens barrel unit according to any one of claims 1 to 3, wherein the zoom lens barrel unit is configured by a barrel.   When the second group moving frame and the third group moving frame integrally move from the wide-angle optical system area to the telephoto optical system, the second lens group is indispensable at least for zooming and focusing adjustment. 2. A fixed gap is provided at a contact portion in a rotational direction between the second group moving frame and the third group moving frame in order to secure an air space of the third lens group. Or 2 zoom lens barrel units.   In zooming operation, when the second group moving frame and the third group moving frame integrally move in a straight line from the wide-angle optical system region to the telephoto optical system direction, or from the telephoto optical system region to the wide-angle optical system region direction. If the air distance between the second lens group and the third lens group is within the range of the wide-angle optical system area of the optical system to the telephoto optical system area, Or the zoom lens barrel unit according to any one of claims 1 to 3, wherein the zoom lens barrel unit is located on the closest side in focus matching adjustment. Along with the zooming operation, within the range from the wide-angle optical system area to the telephoto optical system area, the second group moving frame and the third group moving frame are reduced, and the air space between the second lens group and the third lens group is reduced. When moving in a straight line in the direction to move, or during focus adjustment, either the second group moving frame or the third group moving frame is stationary and the other second group moving frame or the third group The moving frame moves in the direction in which the air gap between the second lens group and the third lens group increases, that is, from the infinite side to the close side direction,
On the other hand, with the zooming operation opposite to the above, within the range from the wide-angle optical system region to the telephoto optical system region, the second group moving frame and the third group moving frame are the second lens group and the third lens unit. When the lens unit moves integrally in a straight line in the direction in which the air interval increases, and when adjusting the focus matching, either the second group moving frame or the third group moving frame is stationary and the other of the second group moving frame is stationary. The second group moving frame or the third group moving frame moves in a direction in which an air interval between the second lens group and the third lens group is reduced, that is, in the infinite direction from the closest side. The zoom lens barrel unit according to any one of the above.   The cylindrical ring part arranged in a part of the second group moving frame and the cylindrical ring part arranged in a part of the third group moving frame are fitted so as to be capable of sliding and rotating and moving in a straight line. 1 or 2 zoom lens barrel unit. When the air gap between the second lens group and the third lens group is expanded to a predetermined interval in accordance with the zooming operation by the rotary drive ring that rotates in one direction in conjunction with the one drive motor. The focus adjustment adjustment is performed by moving the air gap between the second lens group and the third lens group in the reduction direction by rotating the rotary drive ring in conjunction with the drive motor in the opposite direction. With
When the air gap between the second lens group and the third lens group is reduced to a predetermined interval in accordance with the zooming operation by the rotary drive ring rotating in the other direction of the one drive motor, the drive is performed. 5. The focus matching adjustment is performed by moving an air gap between the second lens group and the third lens group in an enlargement direction by rotating a motor in the opposite direction. The zoom lens barrel unit according to any one of the above.   At the time of zooming, the outer helicoid screw of the second group moving frame that supports the second lens group and the outer helicoid screw of the third group moving frame that supports the third lens group are shared with the inner helicoid screw of the main barrel. When the focus adjustment is adjusted, the second group moving frame and the third group moving frame are temporarily disengaged, and the second lens group remains stationary while the screw is engaged. 3. The zoom lens barrel unit according to claim 1, wherein the zoom lens barrel unit is configured so that only the three lens groups rotate and move straight forward.   A through hole is formed in the outer wall of the main barrel at a position corresponding to the inner helicoid valley of the main barrel, and a change in the amount of reflected light of the projected light can be detected in correspondence with the through hole. In addition, the reflection type photosensor is disposed, and a white paint or a white seal for detecting a position signal is formed on a portion obtained by cutting a part of the peak of the outer helicoid screw of the second group moving frame into a planar shape. 3. The zoom lens barrel unit according to claim 1, wherein the zoom lens barrel unit is applied or affixed.   The drive ring can be rotated 360 ° or more in the forward and reverse directions with power from the drive motor unit, and the guide shaft that is implanted in parallel with the optical axis is formed in the third group moving frame. 3. The zoom lens barrel unit according to claim 1, wherein the zoom lens barrel unit is fitted into a rectangular hole and is integrally rotated while sliding the third group moving frame in the optical axis direction.   The friction piece having the elastic characteristics arranged in a state protruding from a valley surface of the outer helicoid from a rectangular hole formed in a side wall portion of the outer helicoid of the second group moving frame is placed in the second group moving frame. The arcuate protrusion housed and disposed at the center of the friction piece always slides in contact with the inner helicoid peak of the main barrel, thereby applying a frictional force to the second group moving frame. The zoom lens barrel unit according to claim 2, wherein:   An imaging apparatus using the zoom lens barrel unit according to any one of claims 1 to 12 as an imaging zoom lens barrel.   13. A camera using the zoom lens barrel unit according to claim 1 as an imaging zoom lens barrel.   A portable information terminal device, wherein the zoom lens barrel unit according to any one of claims 1 to 12 is used as a zoom lens barrel of an imaging function unit.   A cellular phone comprising the zoom lens barrel unit according to any one of claims 1 to 12 incorporated in an imaging function unit.

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